No heater blower motor after dash replacement??

[YGETV8]

Okay... I did a search and checked all that was recommended (hot wire motor: fine; volt meter on all wires: fine), but still no go on ANY speed on my blower motor. I am wrapping up my dash install (PITA) and am wondering if I just plain broke the speed switch upon removal of the head unit? Are they that fragile? Seems most lose high speed or the lower speeds, not ALL?!

Just double checked and I've got 13.4V to ALL positions on the head unit switch and at the resistor under the hood all the time when on heat or AC or vent? Is this a sign that the switch is bad?

Thanks,

 

[Steve Wood]

Okay, Salvage will correct my mistakes.. LOL

Power thru the switch comes from the AC fuse which should be hot when the key is in "run". Be sure the fuse is not zapped.

With the key in "run" and the selector on heater (or anything but off), go under the hood to the brown wire going to the resistor block. It should now be hot. Is it?

If so, then put the fan speed switch on medium #1 (one position up from low) and see if the tan wire on the resistor is hot.

Let us know.....

 

[RobS]

Ok, you have 13 volts going into the resister. What do you have going out of the resister? What do you have at the motor itself? Did you see if you have 0 ohms at the ground?

 

[RobS]

Wow Steve, You must have posted when I was typing!!!!

 

[tc86gn]

Check the relay?

 

[Steve Wood]

laughing...yep...

I am a bit confused because he says he has voltage on all the resistor terminals all the time which makes it sound like the switch is shorted inside..but his fan should run unless the relay is popped. So, it sounds like at least a couple of problems...possible shorted switch and a bad relay....

Wonder if the fan runs if you take the battery straight to the purple wire coming out of the relay?

 

[YGETV8]

Thanks for the replies! Okay... let me make sure I have this right! The resistor is the little thing that bolts into the top of the heater box and has spring type wires on the inside? And the relay is bolted to the front of the heater box? Right?

Just checking myself!

 

[Steve Wood]

yep

 

[YGETV8]

Well, I accidentally discovered that if I put a test wire on the ground at the blower motor I have full control of the blower speeds!? BUT, on high speed the wire gets hot pretty quickly like it has too much load. Is the head unit grounded in dash? Maybe since I don't have the dash in completely the system isn't fully grounded?

I'm gonna run a 10 gauge supplemental ground if it still does it upon reassembly! Any other ideas? Thanks,

 

[RobS]

Sorry its been awhile. Try cleaning the existing ground at the connection and where it makes contact at the blower. I think I had a coroded termanal once but it was on a 77 olds.

 

[Steve Wood]

Jay, I am not sure where the wire actually goes to ground...it is not obvious at first glance....I will try to find it in the book...you may not have connected the ground point yet.

 

[Steve Wood]

I believe the wiring harness goes thru the firewall at the bottom left hand corner of the hvac box under the hood (looking from the front) and the ground wire emerges from the harness under the right hand side of dash when it comes thru the firewall and goes to ground somewhere in that area. I guess look for a unconnected black wire under the right hand side of the dash near the kick panel area.

 

[YGETV8]

OMG! That was SIMPLE! Thanks all! Steve, as usual, you hit the nail right on the head!

The GN has been sitting untouched for a week now as I was preparing the WE4 for track duty last Wed. night. Well, after apparently popping a headgasket while racing in it, I wasn't real anxious to work on more TRs!

Just went out, found the ground wire exactly as you stated, Steve, bolted it up and everything works fine! Duh! I even KNEW that there were some wires hanging over there, but didn't even begin to think that it was for the blower motor!

Thanks!

Jay